SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c2d51f0a7bd4952e642308682bed192c50eb863a2d67fdc534e5f0654f3c48e' 
  AND token = 'CP3/j/lxuEfvRqzQq+n/5fCdKINEZuXaugTkWRMm9g0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}